Abstract:

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Fabrication of friction reducing and anti-wear surface with regular micro/nanostructures is a hotspot of surface engineering studies nowadays. We present a simple and easily-controlled method for fabricating stainless steel-based nanostructures surface. First, by strictly controlling the number of femtosecond laser pulses, two kinds of nanostructures are fabricated. Then, forming mechanisms of nanodots and ripple structure are analyzed. Lastly, we obtained uniform large-area nanodots and ripple structures by adjusting the repetition rate of laser focus accurately. Therefore, this technique will provide a good method to investigate the tribological properties of controllable nanotexture surface.

Abstract: A 775nm femtosecond laser is applied to single crystal silicon by direct-write processing
in air. A series of holes are drilled with 150fs duration pulses, various numbers of laser pulses and
laser fluences on silicon wafer. Different laser parameters and material properties influence the size
of fabricated holes. The diameter and depth of holes are gradually enlarged with the increase of
laser fluence and pulse number. The periodic ripple structure on silicon surface is found and
explained at the same time.

Abstract: The periodic microstructures on 65Mn plate were induced by the irradiation of the femtosecond laser with the laser wavelength of 800 nm and the pulse length of 130 fs. The parallel periodic ripples structures were observed at the laser fluence of 1 J/cm2 with different pulses number( N=5,50,400,800) which lied parallel to the laser electric polarization field vector. For 400 pulses, the nano-holes arrays were generated to interrupt the consistent ripples structures.For 800 pulses, initial nano-holes evolution to the grooves, which the direction were uncertainly. Further experiments have been made to induce large area consitent ripple structures by scanning, at the laser fluence of 1 J/cm2 with speed v=500μm/s. 2D arrays were induced by accurate processing control

Abstract: With femtosecond laser pulse (130 fs, 800 nm, 1 kHz pulse repetition frequency) irradiation on Au/Cr film stack, several nanostructures were obtained. The influence of laser parameters such as fluence(0.5J/cm2,2J/cm2) and the number of pulse were investigate. With single pulse irradiation, the nanoline and periodic ripple structures were obtained for the pulse fluence of 0.5J/cm2 and 2J/cm2, respectively. The formation mechanism of those nanostructures were discussed.

Abstract: In this paper, high quality grooves were fabricated by femtosecond laser pulse on sapphire surface. Grooves were fabricated under different experimental conditions. The lateral and vertical machining precision was evaluated by scanning electron microscopy and profilometer. High quality grooves could be obtained at the condition of low pulse energy, high scanning-speed and increasing the number of laser scans. The relationship between the width and depth of the groove and the key parameters of femtosecond laser micromachining system was studied. Several samples of the high quality grooves were obtained by femtosecond laser pulses. High quality grooves have a potential application of the fabrication of sapphire-based devices.